NO. 12 FLYING APPARATUS OF BLOW-FLY RITTER II 



Structures proper, as surfaces of attachment for the muscles. (See 

 Chapter VI.) 



Near the root of the wing there are found two large openings in 

 the lateral wall of the thorax, through which direct muscles of flight 

 pass to the wing joints: the foramen prrealare (pi. 2, fig. 3, 0) and 

 the foramen postalare (pi. 2, fig. 3, oj. 



4. The Wing 



a. general observations 



The wing of CaUiphora vomitoria (pi. 3, figs. 5, 6; pi. 5, figs. 15- 

 17) is, when fully expanded, irregularly oval. It is, according to 

 the size of the fly, usually 8.5 to 11 mm. long and 3.4 to 4.6 mm. in 

 maximum width. Its horizontal projection (outline) has an extent 

 of from 20 to 40 square millimeters. Its anterior margin appears 

 as a continuous convex line. The curvature is slight at the base 

 and in the middle, but increases distaliy and is most marked at the 

 tip of the wing. The posterior margin is, on the whole, convex like 

 the anterior, but notched in three places. The most distaliy situated 

 notch is insignificant and situated a short distance distaliy from the 

 middle of the wing. The two other notches are deep incisions and 

 situated, proximally, near the root of the wing. They separate two 

 small lobes from the main portion of the wing. The proximal lobe 

 (nearest the body) is the squamula (text figure 2; pi. 5, figs. 15, 17, 

 Sq), the distal lobe which lies between the two deep incisions is the 

 lobulus (text figure 2; pi. 5, figs. 15, 17, /o). 



B, THE VEINS AND FOLDS 



The wing is, as Marey recognized in 1869, somew^hat Vv^arped and 

 slightly convex above. Targe and small folds, the former up to 

 100 ju, in height, traverse the wing longitudinally. In the proximal 

 part of the wing 8, and in its distal part 10 folds are to be dis- 

 tinguished. These folds decrease in height distaliy as they approach 

 the margin of the wing. The anterior large folds are nearly parallel 

 to the anterior margin of the wing, and extend to its end ; the 

 posterior smaller folds radiate somewhat in a fan-shaped manner 

 and extend obliquely outward and backward. These folds dis- 

 appear before reaching the margin of the wing. The posterior por- 

 tion of the wing is creased by very small folds. These folds are 

 numerous, closely crowded and directed backward and outward 

 (pi. 5, figs. 15-17)- 



